Submission #34572

#	Time	Username	Problem	Language	Result	Execution time	Memory
34572		sinhriv	Watching (JOI13_watching)	C++14	50 / 100	1000 ms	20968 KiB

watching

#include <bits/stdc++.h>

using namespace std;

const int N = 2202;

int n, p, q;
int a[N];
int f[N][N];

int main(){
	if(fopen("1.inp", "r")){
		freopen("1.inp", "r", stdin);
	}

	scanf("%d%d%d", &n, &p, &q);

	for(int i = 1; i <= n; ++i){
		scanf("%d", a + i);
	}

	p = min(p, n);
	q = min(q, n);

	sort(a + 1, a + n + 1);

	int low = 1, high = 1e9, ans = 1e9;

	while(low <= high){
		int w = (low + high) >> 1;
	
		memset(f, 60, sizeof f);
		f[0][0] = 0;

		bool ok = false, debug = false;

			
		for(int j = 0; j <= p; ++j){
			deque < int > one, two;

			for(int i = 1; i <= n; ++i){
				while(!one.empty() && a[i] - a[one.front() + 1] + 1 > w){
					one.pop_front();
				}
				while(!two.empty() && a[i] - a[two.front() + 1] + 1 > w + w){
					two.pop_front();
				}
				if(j > 0){
						while(!one.empty() && f[one.back()][j - 1] >= f[i - 1][j - 1]) one.pop_back();
						one.push_back(i - 1);
				}
					while(!two.empty() && f[two.back()][j] >= f[i - 1][j]) two.pop_back();
					two.push_back(i - 1);
				
				if(!one.empty()) f[i][j] = min(f[i][j], f[one.front()][j - 1]);
				if(!two.empty()) f[i][j] = min(f[i][j], f[two.front()][j] + 1);
				

				if(i == n && f[i][j] <= q){
					ok = true;
				}
			}
		}


		if(ok == false){
			low = w + 1;
		}
		else{
			ans = w;
			high = w - 1;
		}
	}

	cout << ans;

	return 0;
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:35:20: warning: unused variable 'debug' [-Wunused-variable]
   bool ok = false, debug = false;
                    ^
watching.cpp:13:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen("1.inp", "r", stdin);
                               ^
watching.cpp:16:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d", &n, &p, &q);
                             ^
watching.cpp:19:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", a + i);
                     ^

• Subtask 1: 50 / 50
• Subtask 2: 0 / 50